The primary objective of the Clinical Core (CC) is to provide patient access and quality data collection including quantitative radiologic analysis to support the SCCOR in COPD at the University of Pittsburgh. To achieve these objectives, the research proposed will accomplish the following specific aims: A1. To access our diverse well characterized patient populations to efficiently recruit subjects for Projects 1 and 4 and maintain accessibility to tissue for Project 2. A2. To successfully assist in the execution of complex protocols, data collection and transfer of data to the ITBC core. A3. To apply quantitative computed tomography to the phenotypic characterization of subjects with COPD and to longitudinal assessment of disease progression and outcome. This CORE is ideally positioned to meet these goals because it combines the strengths of collaborators with a past history of productivity in subject recruitment, and state of the art clinical, physiologic and quantitative radiographic characterization. It will ensure access to the well-characterized cohorts of the 3700 subjects of the Pittsburgh Lung Screening Study (PLuSS) and Emphysema COPD Research Center (ECRC) and its strong track record of contribution to 7 NHLBI funded clinical research contracts. In addition it will leverage off of access to the infrastructures of the NHLBI sponsored LTRC and the University of Pittsburgh Tissue Resource as well as a very active lung transplantation program to ensure access to high quality lung tissue. The third aim of this CORE extends the collaboration of the Radiology Research Group at the University of Pittsburgh and the Whole body Imaging Core of the (CAPTURE Centre to create a force with an international reputation in quantitative imaging who are each long term collaborators with Dr. Sciurba. We propose an iterative interaction between the clinical researchers on this project and the powerful imaging team. The preliminary data presented in project 1 and expanded upon in the clinical core reveal the existing structure and the strength of the existing collaboration and confirms the strong potential of this approach in meeting our goals of creating a new classification system for COPD in project 1, and offering innovative strategy for patient selection and outcome assessment in the context of disease modifying interventions such as in our project 4.